(Another) Dave and I agree that Bewilder Box was absolutely superb and well worth visiting. To put that in context, we had a 7-hour round trip (including congestion on the M25) from Coventry to Brighton. The puzzles were a nice mix of pen-and-paper (codes, hidden messages, etc.) and object interaction (push this, twist that, and so on). The game starts before you get into the room with the hosts getting into character and leading you in. The "Quantum Mechanic", I found out later, goes in and fixes problems with the room if something has been overlooked during the reset process, which is a nice way of handling problems in-character - not that anything went wrong on our visit.
Extra clues are also handled smoothly via D.A.V.E. (ye gods, there's another one) the Artificial Intelligence, which is a much better system than simply having one of the hosts come in. Other places do the latter and it effectively disrupts the setting when the team have supposedly travelled somewhere (or somewhen) a long distance away. Bewilder Box has everything nicely integrated together. Thanks to this game, I plan on making more of an effort to visit other escape rooms, although I will be starting closer to home.
Oh, and we finished with somewhere between 15 and 16 minutes left - the clock didn't get stopped immediately, so it's a little hazy. Ok, so *one* thing went wrong, then; what do you expect with that much Dave in one place?